Hoo-wee! What’s that smell? Is that mustard gas? Man, someone musta let one, eh! Or musta left the lid off the composter… Whoever did it shouldn’t weasel out of it. It’s not fair at all; they oughta do the right thing without being badgered. …What?
Actually, that musty, not to say mephitic, miasma is wafting your way courtesy of a mustelid. So what’s a mustelid? Is it a kind of worm or mollusc? Perhaps a plant, like a mustard green? No, it’s closer to a mus musculus, but longer and larger. If your kind of vermin is ermine, or if you like to think of mink, you’re on your way to the source of the stink.
Yes, the mustelids are a family of carnivorous critters (in Latin the Mustelidae) with long bodies, short legs, fur – often quite luxuriant – and musk glands. The must in this word is not related to the musk gland, nor to the word musty; rather, it’s from mustela, Latin for “weasel”. And along with the weasel you have the ferret, the otter, the badger, the ermine, the stoat, the mink, and the wolverine… and, until recently reclassified, the skunk (now reclassified, fittingly, as Mephitidae).
The elid gives the word a fairly good biological – specifically taxonomical – flavour; one thinks quickly of annelids, for instance. But actually the morpheme boundary is at id, and there are plenty more taxonomic words included by that: hominid would be closest to home. The must is as down to earth in taste as the id is scientific; one may think of freshly crushed grapes, or imperatives, or some longer words: you must muster the mastery to remove the mustard from your mustache. In the middle of all this you may also see tel, which may seem delicate or may have the telling air of a report. Looking at the meeting of these two opposite ends with the telling middle, you may call it dualism, but with armed scent glands, I call’t duelism.
Thanks to Elaine Phillips for suggesting mustelid.